app: sound and the reading play receptions the instant they land, so bursts clump, cues click and the mix clips #709

Component: app

What happens

Three things Kasper hears (27 September):

• Clicks. A cue starts at ac.currentTime (app/src/sound.js:608) with no margin. When the audio thread is already past that instant, the start of the attack is lost.
• Clipping. The master bus has no limiter. Cues, the bed and the music sum, and past 0 dBFS they distort.
• Clumps. BLE frames land in batches. Measured over 30 days on the ingestor DB (feat(app): make every recorded reception audible, one instrument per type (+ sound tweaks) #470), 39.2% of consecutive receptions per hunter share a timestamp, in groups of up to 40 (sound.js:125-131). The coalescer lets one cue through per 60 ms, so a clump of 40 sounds as one, and the reading shows it in one step.

Decided (Kasper, 27 September)

1. A limiter on the master bus.
2. Cues scheduled 20 to 50 ms ahead of currentTime instead of on it.
3. A playout buffer of 1 s. The sound, the HUD, the ticker, the map's pulse and the float readout get each reception 1 s after it lands. A clump is spread at the cue gap (60 ms), closer when that does not fit in the second, so the delay never grows past 1 s. Capture, the store and MQTT keep the real rx_at. A fixed second, not a setting.